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How many light bulbs?

Victor

Member
Joined
10 Jun 2013
Messages
298
Location
Brazil
Hi there. I'll set up a new tank, a large one, 200 cm X 70 cm X 50 cm (height), 700 L total. What's the best lighting set up, 30 x 7w led light bulbs (210 w total, 16750 lumens) or 40 x 7w led light bulbs (280w total, 21000 lumens)? I'm quite undecided, 30 or 40 light bulbs? Please, let me know your opinion. Thank you.
 
If you can afford it, always go for the maximum amount, because LEDs can be dimmed (and run cooler when dimmed).

FYI, my tank is 60x45x45, and I have 156.5w worth of LED.

The problem is this kind of led can't be dimmed. It's a common light bulb, same of the picture below. Despite this, 280 w over 700 L doens't seem to much. The lights will be 8 cm above surface level (light angle is 100º).
led 7w 100º.png
 
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Here's the lighting scheme. Each black dot will be a 7w light bulb. They will be well distributed over all tank width and lenght. It seems a good idea?

esquema iluminação.jpg
 
@Victor Sorry didn't realized you were going the DIY route. I think this is as far as my advise will go. I am not sufficiently educated in DIY lighting. This said, why not buy an aquarium light directly? Is it the cost?
Yes, because it's too expensive.
 
philips-bulb-jpg.jpg


If cost is an issue, it might be cheaper to just buy 5 x 50w LED bulbs. (the plastic frosted cover is removable).
I'm using these 50w bulbs as my video lights.
 
Hi there. I'll set up a new tank, a large one, 200 cm X 70 cm X 50 cm (height), 700 L total. What's the best lighting set up, 30 x 7w led light bulbs (210 w total, 16750 lumens) or 40 x 7w led light bulbs (280w total, 21000 lumens)? I'm quite undecided, 30 or 40 light bulbs? Please, let me know your opinion. Thank you.
78"...185 gallons.
Amazon product ASIN B08VJB6G8V
What about some bigger floods over so many small bulbs?

Two 2-packs... 20,000 total lumens.
6500K.
62 pounds for 4 total lights.
Amazon product ASIN B093GQ8LNJ
 
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I thought about floodlights but the problem is that the light would be very concentrated over some areas at the contrast of some dim areas (between the floodlights). With numerous small bulbs it's easier to get a more uniform lighting. I think I'll put 210w of led in total (17 k lumens). It seems enough.
 
If you cant make a dimmable DIY light I would at least make sure you can easily raise it further up from the water surface if needed, otherwise youre gonna have a very difficult time getting everything balanced I think
 
If you cant make a dimmable DIY light I would at least make sure you can easily raise it further up from the water surface if needed, otherwise youre gonna have a very difficult time getting everything balanced I think
Unfortunately will not be able neither to dim the lights nor to increase the distance from water . The light bulbs would be 7 ~ 8 cm from water surface and will remain fixed in a wood cap. So in this case it's better to use less light than more, ins't it? 210 w of led over 700 L is medium light?
 
I thought about floodlights but the problem is that the light would be very concentrated over some areas at the contrast of some dim areas (between the floodlights). With numerous small bulbs it's easier to get a more uniform lighting. I think I'll put 210w of led in total (17 k lumens). It seems enough.
Yea more is better. I'd convince you otherwise " if" you didn't have that height restriction of 7-8 cm.
8cm up and 100 degrees gives a spot size of 19cm in diameter.
Your pattern is 44 bulbs. 4x11
Your 17.5 and 15cm on centers look ok.
With that kind of design and even spacing your initial lighting "may"create a center hot spot though.
Gets much better with depth.
Advantage of floods is you can uneven space them to actually get a more even spread than you get with multiple bulbs like that.
Gets complicated doing the same thing with many bulbs.
Bulb spacing should be wider on center from the middle getting progressively smaller toward the edges. Overlapping cone thing.
See at about 10 minutes in what I mean about floods. Same concept applies for your multi bulb array.


A bit nit picky and since I haven't seen nor tested that large of an array the "imbalance" may not be that significant.
Second point is s floods can be balanced to avoid hot spots and dim spots.
Actually opaque bracing is more of an issue.
Food for thought.
Keep in mind cameras and meters are a better judge of these imbalances. Visually you may not notice them.
 
As to " how strong is my array " well prefer to measure it. One issue though us since atm you can't t dim it you need to ve cautious at startup if you have a low biomass of plants.

Water surface average par est is 134 @ 14000 lumens.
assuming most light is entrained in 14000 sq cm.
200 @ 21000 lumens
 
Yea more is better. I'd convince you otherwise " if" you didn't have that height restriction of 7-8 cm.
8cm up and 100 degrees gives a spot size of 19cm in diameter.
Your pattern is 44 bulbs. 4x11
Your 17.5 and 15cm on centers look ok.
With that kind of design and even spacing your initial lighting "may"create a center hot spot though.
Gets much better with depth.
Advantage of floods is you can uneven space them to actually get a more even spread than you get with multiple bulbs like that.
Gets complicated doing the same thing with many bulbs.
Bulb spacing should be wider on center from the middle getting progressively smaller toward the edges. Overlapping cone thing.
See at about 10 minutes in what I mean about floods. Same concept applies for your multi bulb array.


A bit nit picky and since I haven't seen nor tested that large of an array the "imbalance" may not be that significant.
Second point is s floods can be balanced to avoid hot spots and dim spots.
Actually opaque bracing is more of an issue.
Food for thought.
Keep in mind cameras and meters are a better judge of these imbalances. Visually you may not notice them.
Thank you, Oreo! I made another lighting scheme (look attached picture). I decided to reduce the amount of light bulbs to just 30 (210 w total), they're now more concentraded at the sides to provide a more difuse lighting. Do you think 210 w of led is enough or too little?
 

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I can’t advise you on the light set up I’m afraid, don’t know enough about DIY ing lights, but would certainly advise that you consider having some diffusion available at outset. Even something as simple (and cheap) as the grey fly netting you can use to make fly screens will act to diffuse light somewhat. If you start out with a couple of layers between light and water surface (and maybe a bit extra spare) you can then add/remove as the tank grows in and stabilises.
 
You could wire the lights as 2-3 individual circuits. So, for example, you could have 3 switches on the light. #1 controls 10 lights; #2 controls 10 lights: #3 controls 20 lights. This way you could have options of 10, 20, 30 or 40 lights on.
 
Thank you, Oreo! I made another lighting scheme (look attached picture). I decided to reduce the amount of light bulbs to just 30 (210 w total), they're now more concentraded at the sides to provide a more difuse lighting. Do you think 210 w of led is enough or too little?
Yep that is the idea ...
Should be pretty decent medium lighting .
Led efficacy looks to be about 75 lumens/ watt
Depends on what you want to grow.

You could get a cheap lux meter to get a ballpark reading.
I' m a bit leary on phone apps but I think that depends on the software and what phone sensor they use/ have.
 
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